Columbia, Mo. ? In a crazy ninth inning, Kansas University’s Tony Thompson hit a game-tying grand slam in the top of the frame, but Ryan Ampleman’s walkoff solo home run gave Missouri a 13-12 victory Sunday in Big 12 baseball action.

The loss dropped the Jayhawks to 35-18 overall and 13-11 in the Big 12. MU improved to 30-23 overall and 16-11 in the conference.

Missouri took two of three games from No. 23 Kansas over the weekend.

The Jayhawks trailed by as many as six runs on Sunday, but rallied for five runs in the top of the ninth. Pinch hitter James Stanfield led off the inning with a walk and scored on Brian Heere’s RBI single. After a Buck Afenir walk loaded the bases, Thompson crushed an 0-1 pitch for his first career grand slam, tying the score at 12.

After a flyout in the bottom of the ninth, Ampleman slammed Colton Murray’s 2-0 offering over the centerfield fence to give Missouri the dramatic victory.

Kansas trailed, 6-1, after two innings. KU starting pitcher Brett Bollman left the game after 11/3 innings, his shortest start of the season.

The Jayhawks fought back in the middle innings, though, with the help of Tiger miscues. In the fourth, KU scored two runs on a walk, a passed ball, an RBI single, a double and a wild pitch.

After Missouri scored three runs in the bottom of the fourth to take a 9-3 lead, Kansas loaded the bases in the fifth with the middle of the order due up. Robby Price was hit by a pitch, which cut the deficit to 9-4. Missouri quickly ended KU’s bases-loaded threat with perhaps the defensive play of the day. KU’s Brian Heere connected on a line drive, but Michael Liberto caught it, then doubled up the runner at second base to stall KU’s momentum.

Thompson’s 17th home run is tied for the second-most by a Kansas player in a season. His 71 RBIs are also tied for the second-most by a Jayhawk.

Thompson and Brian Heere were the only two Kansas players with two hits against Missouri on Sunday.

Kansas will look to bounce back in its final Big 12 series against Kansas State. The Jayhawks and Wildcats will kick off their three-game series at 6:30 p.m. Friday in Manhattan.

Saturday and Sunday’s games will be played at 6 p.m. in Lawrence.